How I can export complete scene from blender to json file to use it with three. Js
The Blender exporter might still support this, but you'd need to switch from THREE.ObjectLoader to THREE.JSONLoader to import your model into three.js. I'm not sure how well-supported that is overall.

The other option, possibly more reliable, would be to use another of Blender's export formats that three.js also supports. I'd suggest trying FBX and glTF (addon) to get started. These work with THREE.FBXLoader and THREE.GLTFLoader respectively.